Vortex amplifier with chamfered pickoff orifice



L. R. ERWIN Feb. 24, 1970 VORTEX AMPLIFIER WITH CHAMFERED PICKOFF ORIFICE Filed Feb. 15, 1968 TIGJ T'IG. 3

INVENTOR LOUIS R. ERWIN ATTORNEY United States Patent U.S. 'Cl. 137-815 11 Claims ABSTRACT OF THE DISCLOSURE A laminated vortex amplifier in which the pickoff orifice is chamfered to obtain a non-oscillating pickoff signal.

CROSS REFERENCE TO RELATED APPLICATION The vortex amplifier of this invention is of the general type disclosed in copending application Ser. No. 705,779, filed Feb. 15, 1968 assigned to the assignee of this application.

BACKGROUND OF THE INVENTION In a vortex fluid amplifier, the output pressure (P is 4 measured at a point downstream from the pickoff orifice. Some of the fluid from the cone shape stream that exists from the amplifier vortex chamber enters the pickoff orifice. The amount of fluid entering the pickoff orifice at a given time is dependent upon the magnitude of the fluid divergence in the cone shape stream, and this degree of divergence depends upon the magnitude of the control pressure (P in the amplifier. Thus, as P is increased, P is decreased because the amount of fluid entering the pickoff orifice is decreased. One of the principal problems in vortex fluid amplifiers is oscillation of the pickoif signal, namely, oscillation of F for a given P SUMMARY OF THE INVENTION In this invention, the vortex body is of a laminated construction and the pickoff orifice is formed as an opening in one of the body laminae. This opening is chamfered at its inlet end, and it has been found that this chamfering of the pickotf orifice eliminates the problem of oscillation of the pickoff signal. The reason that chamfering has this desirable effect is not known with complete certainty, but it is believed that this chamfering prevents turbulence caused by a sharp edge at the pickolf orifice and that this elimination of turbulence eliminates the signal oscillation problem.

It is an object of this invention, therefore, to provide an improved vortex fluid amplifier.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims, and the accompanying drawing in which:

FIGURE 1 is a transverse sectional view of the vortex amplifier of this invention;

FIGURES 2 and 3 are reduced sectional views of the fluid amplifier of this invention as seen from substantially the lines 2-2 and 3-3 in FIG. 1; and

FIGURE 4 is an enlarged fragmentary sectional view of the pickoff lamina in the fluid amplifier of this invention.

With reference to the drawing, the vortex fluid am plifier of this invention, indicated generally at 10, as illustrated in FIG. 1 as consisting of a laminated body 12. A plurality of flat laminae 14-26, inclusive, are positioned in sur-face-to-surface engagement and secured together so as to constitute the integral whole body 12. As shown in FIG. 1, the laminae 14, 16 and 18 cooperate to form a cylindrical vortex chamber 28 having an inlet 3,496,961 Patented Feb. 24, 1970 30 for supply fluid at pressure P an inlet 32 for control fluid at pressure P and an exit passage 34 disposed centrally of the lamina 18 and substantially axially of the chamber 28.

The lamina 20 which is secured to lamina 18, is formed with a vent passage 36. In the illustrated embodiment of the invention, the lamina 22 in which the pickoif orifice 38 is formed is secured directly to the vent passage lamina 20 so that the pickotf orifice 38 is aligned with the exit passage 34 and spaced therefrom by a distance a. This distance a is the predetermined distance required in the design of each specific vortex amplifier 10 and is readily obtained in the structure of this invention by forming either the lamina 20 of a thickness a or by forming a plurality of laminae of a combined thickness 0. The orifice 38 is readily formed of the desired precise size and the lamina 22 is then machined so as to provide the chamfered surface 40 at the end of the orifice 38. As shown in FIG. 4, the surface 40 is, in a preferred embodiment of the invention, inclined with respect to the axis of orifice 38 at an angle of 45 Also in a preferred embodiment of the invention, each surface 40 extends in a direction parallel to the axis of the orifice a distance between 0.004 and 0.008 inch, indicated at b in FIG. 4. As used herein, the term chamfered surface means an inclined surface having a length b of at least 0.004 inch since it has been found that merely breaking the edge corner of the orifice 38 without providing a surface of this minimum length will not accomplish the purposes of the invention.

The orifice 38 is readily aligned with the exit passage 34 during assembly of the lamina 22 with the other body laminae. The lamina 24 which is secured to the pickotf lamina 22 is formed with a discharge passage 42 for output fluid at pressure P and a cover lamina 26 is secured to the lamina 24.

In the operation of the vortex amplifier 10, supply fluid at pressure P is supplied to the vortex chamber 28 through the inlet passage 30 in the cover lamina 14. Control fluid at pressure P is supplied to the chamber 28 through a tangential inlet 32 so that fluid will issue from the exit passage 34 in a cone shape configuration, with the magnitude of divergence of the fluid in the cone being determined by the magnitude of P Thus, as P is increased, the amount of fluid directed through pickofi orifice 38 is decreased so that P is correspondingly decreased. The result is a readily manufacturable structure in which the output pressure P, does not oscillate at a given P A further advantage of the chamfered pickoff orifice 38 is that it enables greater variation in amplifier design as regards the pickotf spacing distance a shown in FIG. 1. When the pickoif orifice 38 is provided with the chamfered surface 40, the distance a is not so critical and pickoff results are uniform over a range of spacing.

Having thus described an embodiment of this invention, what is claimed is:

1. A fluid vortex device comprising a housing defining a chamber, means for introducing a supply fluid into said chamber, means for imparting a control rotational velocity to said supply fluid in said chamber, an exit passage to said chamber, and means having a pickolf orifice formed therein, said pickoff orifice being entirely positioned a distance downstream from said exit passage and disposed in an aligned relation with said exit passage, said orifice having an inlet end provided with and defined by a radially outwardly inclined continuous chamfered surface.

2. A vortex fluid device according to claim 1 wherein said chamfered surface is disposed at an angle of substantially 45 to the axis of said orifice.

3. The fluid vortex device of claim 1 in which said housing is constructed so that said chamber comprises a cylindrical vortex chamber and in which said exit passage extends substantially axially of said chamber.

4. The fluid vortex device of claim 1 in which said means for imparting said control rotational} velocity is separate from said supply means.

5. The fluid vortex device of claim 1 in which said means for imparting said control rotational velocity includes an inlet for control fluid extending substantially tangentially of said chamber.

6. The fluid vortex device of claim 1 in which said distance between said exit passage and said pickoff orifice is selected to provide a signal downstream from said orifice having signal variations corresponding inversely and in an amplified manner to variations in said rotational velocity in said vortex chamber.

7. The fluid vortex device of claim 1 in which said housing is constructed to define a discharge passage connecting with said pickoff orifice.

8. The fluid vortex device of claim 1 in which said pickofi orifice includes a throat section having a crosssectional area substantially equal to the cross-sectional area of said exit passage.

9. The fluid vortex device of claim 8 in which said pickoflf orifice and said exit passage comprise cylindrical passages of substantially equal diameter.

10. The fluid vortex device of claim 9 in which said pickofl orifice comprises an open cylindrical passage having no obstructions formed therein.

11. The fluid vortex device of claim 10 in which said housing comprises a plurality of flat lamina positioned in surface to surface engagement and secured together so as to constitute an integral whole body, said chamfered pick- Otf orifice being formed in one of said body lamina and being positioned a predetermined distance downstream from said exit passage to provide a signal having signal variations corresponding in an amplified manner to variations in said rotational velocity in said vortex chamber.

References Cited UNITED STATES PATENTS 3,351,080 11/1967 Datwyler et al. l37-81.5 3,276,259 10/1966 Bowles et a1. 137-8l.5 X 3,343,790 9/1967 Bowles 137-8l.5 X 3,366,370 1/1968 Rupert 137-8l.5 X 3,373,759 3/1968 Adams 13781.5 3,426,534 2/1969 Murphy 137-8l.5 X

M. CARY NELSON, Primary Examiner W. R. CLINE, Assistant Examiner 

